Influence of swell on undrained shear strength of expansive Ankara clay

Date

2020-09-01

Author

Deliktas, Ceren
Çokça, Erdal

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

233
views

0
downloads

Expansive clays cause problems throughout the earth, in particular for the locations in arid or semi-arid climate. Ankara (Turkey) is in semi-arid climate and change in moisture content of the reddish-brown expansive Ankara clay causes swell-shrink related movements and damages on lightweight structures. Over-estimation of undrained shear strength of an expansive clay without considering swell amount can lead to failures (i.e., bearing capacity, slope stability, and pile capacity). Since the existence of water significantly affects the engineering properties of the swelling soils, the effect of swell on the undrained shear strength of Ankara clay was researched in this laboratory study. To verify this effect, tests were done on three expansive Ankara clay samples with distinct degree of expansiveness. Expansive clay samples were taken from several sites in Ankara. Before swell-shear test cycle, index properties of the samples were determined. Swelling of the specimens in designed molds and shearing process including 0%, 10%, 15%, 20%, 25%, 50%, and 75% of ultimate vertical swell and 100% swell were followed it. It has been determined that undrained shear strength of the expansive Ankara clay is considerably affected by the amount of swell depending on the test results. The undrained shear strength decreases with increasing water content. It was observed that the shear strength of the specimens was decreased to nearly 70% of its initial value, even at the 10% of ultimate swell, and the undrained shear strength of expansive Ankara clay specimens was lost to a degree of almost 90% of their initial value (i.e., almost complete loss of strength due to swelling), this is one of the major factors causing failure of structures in/on the expansive Ankara clay due to wetting in the depth of active zone.

Subject Keywords

General earth and planetary sciences, General environmental science, Expansive clay, Free swell index, Methylene blue test, Swell percentage, Rate of swell, Undrained shear strength

URI

https://hdl.handle.net/11511/43113

Journal

ARABIAN JOURNAL OF GEOSCIENCES

DOI

https://doi.org/10.1007/s12517-020-05767-z

Collections

Department of Civil Engineering, Article

Suggestions

OpenMETU
Core

Influence of swell on shear strength of expansive soils Deliktaş, Ceren; Çokça, Erdal; Department of Civil Engineering (2016) Behavior of swelling soils is thoroughly investigated since they cause significant hazard to structures all around the world, especially in the regions with climate of arid or semi-arid. These types of soils expand upon wetting and shrink when water is removed. Existence of water significantly alters the shear strength of swelling soils. Therefore, the objective of this study is to examine the influence of swell on the shear strength of expansive soils. For the first series of tests, an artificial expansive...
Effect of cyclic swell – shrink on swell percentage of an expansive clay stabilized by class c fly ash As, Mehmet; Çokça, Erdal; Department of Civil Engineering (2012) Expansive soils are a worldwide problem especially in the regions where climate is arid or semi arid. These soils swell when they are exposed to water and shrink when they dry. Cyclic swelling and shrinkage of clays and associated movements of foundations may result in cracking of structures. Several methods are used to decrease or prevent the swelling potential of such soils like prewetting, surcharge loading, chemical stabilization etc. Among these, one of the most widely used method is using chemical adm...
Stabilization of expansive soils by using red mud Çağlar, Cemre; Çokça, Erdal; Department of Civil Engineering (2019) Expansive soils are generally existing in semi-arid and arid regions of the world. This type of soils expands when they absorb water and shrink when they dry out. Expansive soils are causing problems to the lightweight structures. The purpose of the study is to suggest a cost-effective alternative method for coping with these problems. The widely used traditional method is the stabilization of the soil with the chemical admixtures. In this study; waste red mud and waste fly ash were used as stabilizers. The...
Effect of weathering on the geomechanical properties of andesite, Ankara - Turkey Orhan, M.; Isik, N. S.; Topal, Tamer; Ozer, M. (Springer Science and Business Media LLC, 2006-05-01) Andesite exposed in different parts of Ankara has different weathering categories varying from fresh to residual soil. The geomechanical properties of the andesite are significantly affected by weathering. Buildings constructed especially in completely weathered and residual soil levels of the andesite have some geotechnical problems. In this study, the variation of the geomechanical properties of the andesite due to weathering is investigated in three selected sites of Ankara, through optical microscope, X...
Effect of tectonic processes on biosphere-geosphere feedbacks across a convergent margin Fullerton, Katherine M.; et. al. (2021-04-01) The subsurface is among Earth's largest biomes, but the extent to which microbial communities vary across tectonic plate boundaries or interact with subduction-scale geological processes remains unknown. Here we compare bacterial community composition with deep-subsurface geochemistry from 21 hot springs across the Costa Rican convergent margin. We find that cation and anion compositions of the springs reflect the dip angle and position of the underlying tectonic structure and also correlate with the bacter...

Citation Formats

C. Deliktas and E. Çokça, “Influence of swell on undrained shear strength of expansive Ankara clay,” ARABIAN JOURNAL OF GEOSCIENCES, pp. 0–0, 2020, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/43113.